Illicit Discharge Detection and Elimination (IDDE) Plan Grafton, Massachusetts June 30, 2021 Update Table of Contents Illicit Discharge Detection and Elimination Plan Grafton, Massachusetts 1 Introduction ................................................................................ 3 1.1 MS4 Program ......................................................................................................... 3 1.2 Illicit Discharges ................................................................................................... 3 1.3 Allowable Non-Stormwater Discharges ................................................................ 4 1.4 Receiving Waters and Impairments ...................................................................... 4 1.5 IDDE Program Goals, Framework, and Timeline................................................ 6 1.6 Work Completed to Date ....................................................................................... 7 2 Authority and Statement of IDDE Responsibilities .................... 8 2.1 Legal Authority ...................................................................................................... 8 2.2 Statement of Responsibilities ................................................................................ 8 3 Stormwater System Mapping .................................................... 9 3.1 Phase I Mapping ................................................................................................... 9 3.2 Phase II Mapping ................................................................................................. 10 4 Sanitary Sewer Overflows (SSOs) ............................................ 10 5 Assessment and Priority Ranking of Outfalls .......................... 13 5.1 Outfall Catchment Delineations .......................................................................... 13 5.2 Outfall and Interconnection Inventory and Ranking........................................... 13 5.3 Follow-up Ranking of Outfalls and Interconnections ......................................... 15 6 Dry Weather Outfall Screening and Sampling ....................... 29 6.1 Weather Conditions ............................................................................................. 29 6.2 Dry Weather Screening/Sampling Procedure ..................................................... 29 6.2.1 General Procedure ...................................................................................................... 29 6.2.2 Field Equipment ......................................................................................................... 30 6.2.3 Sample Collection and Analysis ................................................................................ 31 6.3 Interpreting Outfall Sampling Results ................................................................ 34 7 Catchment Investigations ....................................................... 35 7.1 System Vulnerability Factors ............................................................................... 35 7.2 Dry Weather Manhole Inspections ..................................................................... 38 7.3 Wet Weather Outfall Sampling ............................................................................ 39 7.4 Source Isolation and Confirmation ..................................................................... 40 7.4.1 Sandbagging ................................................................................................................. 40 7.4.2 Smoke Testing ............................................................................................................. 40 7.4.3 Dye Testing .................................................................................................................. 41 Illicit Discharge Detection and Elimination Plan i June 30, 2021 7.4.4 CCTV/Video Inspection ........................................................................................... 41 7.4.5 Optical Brightener Monitoring ................................................................................. 41 7.4.6 IDDE Canines ............................................................................................................. 42 7.5 Illicit Discharge Removal .................................................................................... 42 7.5.1 Confirmatory Outfall Screening ............................................................................... 42 7.6 Ongoing Screening .............................................................................................. 43 8 Training ...................................................................................... 44 9 Progress Reporting ................................................................... 44 Tables Table 1-1. Impaired Waters in Grafton .................................................................................................................. 5 Table 1-2. IDDE Program Implementation Timeline ......................................................................................... 7 Table 4-1. SSO Inventory ....................................................................................................................................... 12 Table 5-1. Outfall Inventory and Priority Ranking Matrix ................................................................................ 16 Table 6-1. Field Equipment – Dry Weather Outfall Screening and Sampling .............................................. 30 Table 6-2. Sampling Parameters and Analysis Methods .................................................................................... 32 Table 6-3. Required Analytical Methods, Detection Limits, Hold Times, and Preservatives4 .................... 33 Table 6-4. Benchmark Field Measurements for Select Parameters ................................................................. 34 Table 7-1. Outfall Catchment System Vulnerability Factor (SVF) Inventory ................................................ 37 Figures Figure 1-1. IDDE Investigation Procedure Framework ..................................................................................... 6 Appendices Appendix A – Legal Authority (IDDE Bylaw) Appendix B – Field Forms, Sample Bottle Labels, and Chain of Custody Forms Appendix C – IDDE Employee Training Record Appendix D – Water Quality Analysis Instructions, User’s Manuals and Standard Operating Procedures Appendix E – Source Isolation and Confirmation Methods: Instructions, Manuals, and SOPs Illicit Discharge Detection and Elimination Plan ii June 30, 2021 1 Introduction 1.1 MS4 Program This Illicit Discharge Detection and Elimination (IDDE) Plan has been developed by Grafton to address the requirements of the United States Environmental Protection Agency’s (USEPA’s) 2016 National Pollutant Discharge Elimination System (NPDES) General Permit for Stormwater Discharges from Small Municipal Separate Storm Sewer Systems (MS4) in Massachusetts, hereafter referred to as the “2016 Massachusetts MS4 Permit” or “MS4 Permit.” The 2016 Massachusetts MS4 Permit requires that each permittee, or regulated community, address six Minimum Control Measures. These measures include the following: 1. Public Education and Outreach 2. Public Involvement and Participation 3. Illicit Discharge Detection and Elimination Program 4. Construction Site Stormwater Runoff Control 5. Stormwater Management in New Development and Redevelopment (Post Construction Stormwater Management); and 6. Good Housekeeping and Pollution Prevention for Permittee Owned Operations. Under Minimum Control Measure 3, the permittee is required to implement an IDDE program to systematically find and eliminate sources of non-stormwater discharges to its municipal separate storm sewer system and implement procedures to prevent such discharges. The IDDE program must also be recorded in a written (hardcopy or electronic) document. This IDDE Plan has been prepared to address this requirement. 1.2 Illicit Discharges An “illicit discharge” is any discharge to a drainage system that is not composed entirely of stormwater, with the exception of discharges pursuant to a NPDES permit (other than the NPDES permit for discharges from the MS4) and discharges resulting from fire-fighting activities. Illicit discharges may take a variety of forms. Illicit discharges may enter the drainage system through direct or indirect connections. Direct connections may be relatively obvious, such as cross-connections of sewer services to the storm drain system. Indirect illicit discharges may be more difficult to detect or address, such as failing septic systems that discharge untreated sewage to a ditch within the MS4, or a sump pump that discharges contaminated water on an intermittent basis. Some illicit discharges are intentional, such as dumping used oil (or other pollutant) into catch basins, a resident or contractor illegally tapping a new sewer lateral into a storm drain pipe to avoid the costs of a sewer connection fee and service, and illegal dumping of yard wastes into surface waters. Some illicit discharges are related to the unsuitability of original infrastructure to the modern regulatory environment. Examples of illicit discharges in this category include connected floor drains in old buildings, as well as sanitary sewer overflows that enter the drainage system. Sump pumps legally connected to the storm drain system may be used inappropriately, such as for the disposal of floor Illicit Discharge Detection and Elimination Plan 3 June 30, 2021 washwater or old